CaSO4 and Its Pressure-Induced Phase Transitions. A Density Functional Theory Study

详细信息    查看全文

• 作者：Lourdes Gracia ; Armando Beltr谩n ; Daniel Errandonea ; Juan Andr茅s
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：February 6, 2012
• 年：2012
• 卷：51
• 期：3
• 页码：1751-1759
• 全文大小：370K
• 年卷期：v.51,no.3(February 6, 2012)
• ISSN：1520-510X

文摘

Theoretical investigations concerning possible calcium sulfate, CaSO₄, high-pressure polymorphs have been carried out. Total-energy calculations and geometry optimizations have been performed by using density functional theory at the B3LYP level for all crystal structures considered. The following sequence of pressure-driven structural transitions has been found: anhydrite, Cmcm (in parentheses the transition pressure) 鈫?monazite-type, P2₁/n (5 GPa) 鈫?barite-type, Pnma (8 GPa), and scheelite-type, I4₁/a (8 GPa). The equation of state of the different polymorphs is determined, while their corresponding vibrational properties have been calculated and compared with previous theoretical results and experimental data.